In the United States, chlorinated cake flour is a staple of commerce. Chlorinated cake flour is used in a wide variety of food products, especially chemically leavened food products which are commonly referred to as batter based. Primarily, however, chlorinated cake flour is used in the preparation of high ratio layer cakes. Such layer cakes are referred to as "high ratio" because the sugar-to-flour ratio is substantially in excess of 1:1. More typically, these high ratio layer cakes are in the order of about 1.25-1.30:1. Such high sugar containing layer cakes are desirable because of the texture, flavor, tenderness, and other attributes the high level of sugar imparts to the finished baked good.
Chlorinated cake flours are used in such high ratio layer cakes since chlorinated flour allows the preparation of a finished high ratio baked layer cake having the combination of features of 1) a high specific volume (i.e., low density), and 2) good eating qualities of moistness and tenderness. When unchlorinated flour is used, the resultant finished cake baked good is unacceptably dense and exhibits a poor texture. Furthermore, since chlorination has a mild bleaching effect, the color of white cake is modestly improved when chlorinated flour is incorporated into a layer cake mix.
In commercial practice the extent of chlorination is expressed in ounces of chlorine per 100 lbs of flour ("oz/cwt"). For a chocolate layer cake (not requiring a bleached flour), the flour may be chlorinated to about 2 oz/cwt (1.25 g/kg). A white layer cake may require 3 oz/cwt (1.8 g/kg) and an angel food cake (shortening and egg yolk free type cake) may require up to 4 oz/cwt (2.5 g/kg). Typically, however, chlorination is not a sufficiently strong bleaching operation for cake flour to be incorporated into a white layer cake or an angel food cake and such flour is additionally or further treated with a stronger bleaching agent (e.g., apx 50 ppm of benzoyl peroxide) to further whiten the flour.
As a result of the use of chlorinated flour, Americans have grown accustomed to cakes possessing the desirable attributes of high ratio cakes, particularly both high volume and tenderness.
Notwithstanding the acceptance in the United States of chlorinated cake flour, chemical treatments and chemical additives to foods have become suspect and it is desirable to avoid such treatments and additives wherever possible. In addition, most foreign countries prohibit the use of chlorinated cake flour in their cake products. As a result, these countries do not allow importation of American dry mix products such as cake mixes and the like which contain chlorinated flour.
In view of these concerns and limitations regarding chlorinated cake flour, there have been numerous attempts at developing substitutes for chlorinated cake flour and methods for preparing such unchlorinated cake flours. Indeed, the art contains many references proclaiming the final solution to providing a chlorinated flour substitute. Notwithstanding these optimistic representations, to date, the use of chlorinated flour is still widespread and no commercially feasible substitute or process therefor has yet been developed or adopted.
These various treatments of flour have not been adopted for two primary reasons. First and foremost is their cost. Second is their performance.
Flour milling is a commodity business. The implication of this fact is that the difference between profit and loss are expressed in tenths of cents per pound of flour. As a result, flour milling operations are typically very high volume operations. The practical implication is that a potential substitute for chlorination process whose energy and/or capital costs exceed one penny per pound is essentially uneconomical regardless of any minor improvement in flour baking performance.
Most of the known described flour treatment techniques have not been adopted because either the optimum treatment conditions were too long (leading to excessive capital and/or energy costs) and/or the treatment results in commercial practice are not as beneficial as originally hoped (i.e., the taught methods don't work very well). Also very expensive, relatively speaking, are starch extraction processes wherein the starch fraction is separated from the gluten fraction. With these general observations regarding the deficiencies of known methods for treating flour to obtain a substitute for chlorinated flour and the primary importance of cost in determining the commercial feasibility of a process, the following is a description of particular technical approaches.
Among its effects, chlorination of cake flour mimics the effect of time as unchlorinated flour ages. Thus, one prior art approach to processing of cake flour to impart the properties of chlorination is to accelerate the aging of cake flour. Since chemical reactions are affected by temperature, various processes have been proposed for heating the flour to improve its properties. Thus, for example, in U.S. Pat. No. 3,490,917, normal, soft wheat flour or starch is subjected first to air classification to obtain a low gluten flour. The low gluten flour is heated at a temperature of 100.degree. to 140.degree. C. for about 30 minutes. Then, the treated flour or starch is combined with dried, viable gluten to give a flour useful in cake and sponge recipes. Recently, in British Patent No. 1,499,986, it was shown that the preliminary air classification step is unnecessary.
In U.S. Pat. No. 3,428,461 a method is taught involving heat treating a bread flour for preparing a substitute for chlorinated flour.
Rather than treating flour itself, another approach is to formulate dry mixes using unchlorinated flour to include particular ingredients which compensate for the absence of the beneficial properties of flour chlorination. In this approach, two techniques have been most common. One technique involves selection of particular emulsifier or emulsifier blends to impart one or more properties to the finished layer cake product. (See for example, U.S. Pat. No. 3,597,224 issued Aug. 3, 1971, which discloses addition of a sodium sulfoacetate emulsifier.)
In the other common technique, a pure starch is added in requisite amounts in partial substitution for the cake flour. As a generalization, better cake flours are characterized by low protein contents. Even better cakes are prepared using the pure starch fraction of cake flour. However, extraction of the starch from the cake flour is relatively expensive. Thus, in order to optimize a layer cake formulation using unchlorinated flour, the formulator must balance the improvements obtained from inclusion of the starch component of cake flour against the increase in the cost of such a pure starch containing formulation. Of course, the cost of using pure starch can be reduced by substituting a more functional starch and/or by using less expensive substitutes for wheat starch. An example of this approach is found in U.S. Pat. No. 4,294,864 (issued Oct. 13, 1981 and assigned to The American Institute of Baking) wherein starch and other dry mix ingredients are used to formulate a high ratio cake mix using unchlorinated starch.
Chlorination also affects the temperature at which gelatinization occurs and generally lowers the gelatinization temperature. Thus, another approach in the art has been to partially swell or gelatinize the starch component of cake flour. An example of this approach is found in U.S. Pat. No. 4,157,406 (issued Jun. 5, 1979) wherein unbleached flour is heated to about 49.degree. to 93.degree. C. for one hour up to 10 weeks, preferably about four days, to improve its baking properties. An improvement in this process is described in U.S. Pat. No. 4,259,362 (issued Mar. 31, 1981 to Hanamoto et al.) involving unbleached bread flour. Unfortunately, such long treatment times are economically impractical for a bulk commodity such as cake flour.
GB, A, 1,499,986 (J. Lyons and Company Limited, 1 Feb. 1978) is directed towards high ratio cake mixes comprising a heat treated flour substitute for chlorinated cake flour. However, the heat treatment described does not teach high intensity microwave heating but rather conventional thermal heating or conventional microwave heating. Moreover, thr '986 patent is silent about the use of radio frequency heating.
U.S. Pat. No. 3,428,461 issued 18 Feb. 1969 to W. A. Hatton and E. R. Lowry is directed towards a dry mix for a high ratio cake including a flour component that has been dry heated to 150.degree. to 360.degree. F. (65.degree. to 182.degree. C.) for about one minute to 17 hours. However, the patent does not teach the use of high intensity microwave heating or radio frequency heating.
DE A 2, 442,552 (Flour Milling and Baking Research Association, 13 Mar. 1975) and, equivalently, U.S. Pat. No. 3,974,298 issued 10 Aug. 1976 to Cauvain et al., describes a method for preparing a heat treated flour by heating at 120.degree. to 60.degree. C. for about 5 to 60 minutes.
Given the state of the art, there is a continuing need for new and useful cake flour substitutes for chlorinated cake flour.
Accordingly, it is an object of the present invention to provide new and useful techniques for treating unchlorinated cake flour to improve the baking properties thereof so as to realize a substitute for conventional chlorinated cake flour.
Another object of the present invention is to provide an untreated cake flour substitute for conventional chlorinated cake flour.
Still another object of the present invention is to provide unchlorinated cake flour substitutes for chlorinated cake flour useful in the preparation of a variety of dry mixes for baked goods, including layer cakes.
Still another object of the present invention is to provide methods for the treatment of unchlorinated cake flour so as to provide a treated unchlorinated cake flour product useful in substitution for conventional chlorinated cake flour.
Still another object of the present invention is to provide methods for providing an unchlorinated cake flour substitute for chlorinated cake flour which are economically practical.
Still another object of the present invention is to provide methods for treatment of unchlorinated cake flour for the preparation of chlorinated cake flour substitutes which can be practiced in conventional cake flour milling operations.
Still another object of the present invention is to provide an unchlorinated cake flour substitute for chlorinated flour which upon addition to a dry mix for a layer cake provides improvements in both finished baked goods' volume and texture.
Still another object of the present invention is to provide an economical method for treating unchlorinated cake flour to realize a substitute for chlorinated flour which methods are economically competitive with the capital and processing costs of chlorination of cake flour.
Still another object of the present invention is to provide methods for treating unchlorinated cake flour so as to produce a cake flour substitute for chlorinated flour which exhibits improved baking properties including both volume and texture.
Still another objective is to provide methods for improving the baking properties of an unchlorinated flour that exhibits months of stability with respect to the improvement in baking properties.
Still another object of the present invention is to provide improved flours exhibiting improvements in baking properties.
Still another object of the present invention is to provide dry mixes for high ratio layer cakes which upon preparation into finished baked goods exhibit high volumes and good eating qualities that do not require chlorinated flour or expensive starch fractions.
Surprisingly, the above objectives can be realized and new and useful unchlorinated cake flour substitutes can now be prepared. The present improved cake flour is obtained by radio frequency heating raw unchlorinated cake flours to particular moisture contents.
The present invention provides a further improvement from the process of the parent application in the surprising discovery that radio frequency heating can also be used as well as or in addition to microwave heating. Moreover, radio frequency has been found to be unexpectedly superior to microwave treatment of cake flour. Also, another method has been found to obtain cake flours, especially unchlorinated flours, that have SNU values &gt;400, namely, using radio frequency heating. In another aspect, flours having SNU values higher than 425 and even 450 have been obtained; higher values than obtained through microwave heating to similar moisture contents. Also, flours having SNU values as low as 350, if obtained by radio frequency heating, can be used and provide improved baked goods compared to other treatments, including microwave heating, to equal SNU values.